Holden Racing Team driver Garth Tander has told of his disappointment at losing his seat at Walkinshaw Racing to Scott Pye less than a week after winning the Sandown 500.

But the 2007 Supercars champion has vowed to respond strongly at Bathurst next month as he aims to defend his Enduro Cup crown.

A factory driver for HRT for the past nine years, the off-contract Tander learned on Thursday that he would not secure a new deal with Walkinshaw Racing, which has signed Pye to drive alongside James Courtney for the next three years.

The driver change follows the loss of the team's factory backing from Holden, which will see the famous HRT name shift to Red Bull Racing from next year.

Tander said he had been ready to discuss his future with the team, but the 39-year-old said he could tell "they were not all that interested".

"It's disappointing, the first time that I was in the office after winning the race on Sunday, I was told that I'm no longer required for the future," Tander said.

"So that is obviously disappointing given that I have been a factory Holden driver for nine years, but that's life.

"Clearly the team felt that they needed to make some changes on the back of losing the Holden funding and clearly they decided they needed to make that change.

"It would have been nice to at least have a discussion, but that didn't even take place. That's their decision. Disappointing, but that's motor racing."

Tander said he did not yet know what his next move would be, but suggested he would like to continue in Supercars.

His name has been linked to a return to Garry Rogers Motorsport, where he last raced in 2004, as a replacement for the DJR Team Penske-bound Scott McLaughlin.

"Racing is my life, it's all that I've ever done and it's what I will continue to do," Tander said.

"I've always prided myself through my career on challenging myself to race against the best and in the most competitive environment and Supercars is clearly the most competitive environment at the moment.

"I want to continue to challenge myself so we'll just see what options present themselves for the future."

The three-time Bathurst champion has finished in the top 10 of the championship every year since his title win in 2007 and sits eighth in the standings this season.

Despite losing his seat, Tander remains determined to deliver a strong finish to the season after claiming a drought-breaking win at Sandown - his first since Townsville in 2014.

"I'm just focused on Bathurst obviously in a couple of weeks' time and to try to win a couple of races to finish the year off in style," Tander said.

"Certainly since we have rolled this new car out, it's quite obvious there has been an upswing in performance and it's not like I'd forgotten how to drive and I've remembered how to drive again. I think it's no coincidence that the speed has come back with the change in cars.

"I'll only have a handful of races with that level of equipment available to me at HRT, which is a little bit disappointing and a little bit frustrating because I haven't been able to show what I feel I was capable of doing and we certainly showed that on the weekend.

"That's disappointing, but all we can do now is look forward to the future."